Forces

Overview Video

You can use forces to add movement to grass through time.

Enable wind and play through your scene to see how forces add realism to your animations.

Animation to show wind enabled on a grassy terrain.

Wind

Enable

Clicking in the tick box will enable the wind, but you will need to click play to see the animation of the effects of the wind.

Wind Strength

The Wind Strength slider can be taken to 100%, but manually inputting the numbers means that you can input a Wind Strength value of well over 100%, to simulate gale forces.

Animation to demonstrate the Wind Strength parameter. On the left, the Wind Strength is set to 30% and on the right this is increased to 250%.

Wind Strength Variation

This slider needs to be above 0 (zero) % in order to see any movement in the animation.

In this animation, the Wind Strength Variation is set at 25% on the left (with a Wind Strength setting of 100%), while on the right the slider is up at 100% (with the Wind Strength at 90%).

Turbulence

The Turbulence setting adds a more random movement once play has been clicked.

Again, the slider will take this up to 100%, but you can manually input a higher value.

On the left in this animation, the Turbulence slider is up to 100%, but on the right the value is 500%.

Turbulence Scale

Raise and lower this to increase and decrease the scale of the turbulence.

The Turbulence Scale is set at 0.7% on the left, in this animation, while on the right there is a completely different look, with a value of 5% (for both, the Turbulence is set at 500%).

Noise Type

There are four different options for Noise Type: Turbulence, Wavy Turbulence, Noise and FBM (Fractional, or Fractal, Brownian Motion).

Octaves

Increases and decreases the detail of the Noise Type setting, with a smoother animation at a lower setting, getting more frenetic as the Octave level is raised.

Frequency

Sets the rate at which the turbulence animates.

Higher frequencies will animate more quickly.

Lower frequencies will produce a much slower animation.

Direction

Dragging the slider, or inputting a value, will change the direction of the wind up to 360 degrees.

Direction Object

You can also use a scene object as the source of the wind direction, by simply inputting an object into the link field.

The wind direction will always be dictated by the +Z direction of the object, as with the example Null shown here.

This animation demonstrates the effect of a Cube as the source of the wind direction.

Seed

This setting directly affects both the Wind Strength Variation and the Noise Type settings.

Changing the Seed value will give you different looks in both still frames and animation.

Loop Options

This option helps you achieve a seamless animation, once you reach the end of the Timeline.

Loop Time

Inputting a value one frame higher than the end of the Timeline will ensure you have a perfect loop, with no jumping in your animation.